CN117890824A - Method for rapidly detecting short-circuit current in battery - Google Patents
Method for rapidly detecting short-circuit current in battery Download PDFInfo
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- CN117890824A CN117890824A CN202410224721.4A CN202410224721A CN117890824A CN 117890824 A CN117890824 A CN 117890824A CN 202410224721 A CN202410224721 A CN 202410224721A CN 117890824 A CN117890824 A CN 117890824A
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- Prior art keywords
- self
- current
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- short
- discharge current
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- 238000000034 method Methods 0.000 title claims abstract description 24
- 238000001514 detection method Methods 0.000 claims abstract description 14
- 239000000178 monomer Substances 0.000 claims abstract description 9
- 238000007599 discharging Methods 0.000 claims abstract description 5
- 239000003990 capacitor Substances 0.000 claims description 6
- 238000004146 energy storage Methods 0.000 claims description 5
- 238000000691 measurement method Methods 0.000 claims 1
- 238000002203 pretreatment Methods 0.000 claims 1
- 238000003745 diagnosis Methods 0.000 abstract 1
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 4
- 229910001416 lithium ion Inorganic materials 0.000 description 4
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001453 impedance spectrum Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/367—Software therefor, e.g. for battery testing using modelling or look-up tables
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/385—Arrangements for measuring battery or accumulator variables
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Secondary Cells (AREA)
Abstract
The invention relates to a method for rapidly detecting short-circuit current in a battery, which comprises (1) modeling a power battery monomer by adopting a first-order RC equivalent circuit model; (2) deducing a self-discharge current fitting formula; (3) Determination of open circuit voltage V of power battery cell using voltmeter OCv The method comprises the steps of carrying out a first treatment on the surface of the (4) At a determined open circuit voltage V OCV By means of a constant-pressure source V eq Charging and discharging the power battery monomer; (5) Determining current change i in loop by ammeter d The method comprises the steps of carrying out a first treatment on the surface of the (6) Predicting self-discharge current convergence result I by adopting self-discharge current fitting formula d The method comprises the steps of carrying out a first treatment on the surface of the (7) And determining whether the power battery monomer is internally short-circuited or not according to the self-discharge current convergence result. Compared with the prior art, the invention has the advantages of high diagnosis speed and detection precisionHigh and the like.
Description
Technical Field
The invention relates to a battery detection method, in particular to a rapid detection method for short-circuit current in a battery.
Background
Lithium ion batteries are widely used due to performance advantages, however, the lithium ion batteries have potential safety problems such as thermal runaway and the like. The results of the study showed that more than half of the thermal runaway incidents were associated with internal short circuits in the cells. The lithium ion battery has self-discharge, and when internal short circuit occurs in the lithium ion battery, the self-discharge current is increased, and the effect of monitoring thermal runaway can be achieved by detecting the internal short circuit current.
The current mainstream internal short circuit detection method comprises the following steps: the internal short circuit detection based on the consistency of the batteries is realized according to the principle that the parameters such as the voltage, the current and the like of the batteries are kept consistent under the same working condition, so that the method can only detect the batteries under the same battery pack, and can cause larger errors due to the battery balancing function, and the application scene is greatly limited; the method based on the model can convert the internal short circuit detection problem into the parameter and state estimation problem, but the difficulty of updating the model parameters and keeping the detection precision is high under the complex working condition; based on the electrochemical impedance spectrum method, a data set is constructed, the characteristic distance of the battery to be tested is calculated through data driving, whether the battery is internally short-circuited is judged, and a large amount of data and training are needed. If the self-discharge characteristic of the battery is considered, the internal short circuit detection is performed, and the principle is simple but long-term.
Disclosure of Invention
The invention aims to: aiming at the defects of long time consumption and low precision of the existing method for detecting the short-circuit current in the battery, the invention provides a method for rapidly detecting the short-circuit current in the battery, which is rapid and accurate.
The technical scheme is as follows: the method for rapidly detecting the short-circuit current in the battery comprises the following steps:
(1) Modeling the power battery monomer by adopting a first-order RC equivalent circuit model;
(2) Deducing a self-discharge current fitting formula;
(3) Determination of open circuit voltage V of power battery cell using voltmeter OCV ；
(4) At a determined open circuit voltage V OCV By means of a constant-pressure source V eq Charging and discharging the power battery monomer;
(5) Determining current change i in loop by ammeter d ；
(6) Predicting self-discharge current convergence result I by adopting self-discharge current fitting formula d ；
(7) And determining whether the power battery monomer is internally short-circuited or not according to the self-discharge current convergence result.
Further, in the step (1), the first-order RC equivalent circuit model includes an internal impedance portion and an internal self-discharge loop portion.
Further, the internal impedance portion is formed by an ohmic resistor R 0 Is connected with an RC link in series.
Further, the internal self-discharge loop is partially formed by an energy storage capacitor C eff And a self-discharge resistor R SD And the two are connected in series.
Further, in the step (2), the self-discharge current fitting formula is i d ＝f(V eq ，V OCV ，R eq ，R 0 ，R SD ，C eff ，R 1 ，C 1 …，t)
Wherein V is eq Is a constant voltage source voltage, V OCV Is open circuit voltage, R eq For the internal resistance of the equipment, R 0 Ohmic resistance R of first-order RC equivalent circuit model SD Is a self-discharge resistor C eff R is the energy storage capacitor 1 Resistance of first-order RC link, C 1 Is the capacitance of the first-order RC link.
Further, in the step (6), the prediction mode is to fit the current I by using a least square method d The curve before convergence obtains the relevant parameters, and the residual curve is drawn according to the relevant parameters to obtain I d The converged curve is used for obtaining the self-discharge current convergence result I d 。
Compared with the prior art, the invention has the advantages that:
the invention creatively provides the method for establishing the equivalent circuit model and carrying out internal short-circuit current calculation in a formula fitting mode, and compared with the existing internal short-circuit current detection method, the method has the advantage that the convergence speed is higher under the same precision.
Drawings
FIG. 1 is a flow chart of the method of the present invention;
FIG. 2 is a power cell equivalent circuit model established by the present invention;
FIG. 3 is a schematic diagram of a detection circuit constructed in accordance with the present invention;
fig. 4 is an internal short circuit current convergence curve of the present invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
According to the internal impedance of the power battery, an equivalent circuit model can be established, and the equivalent circuit model comprises an internal impedance part and an internal self-discharging loop part. Wherein the internal impedance is defined by ohmic resistance R 0 In series with an RC link, where R 1 Resistance of first-order RC link, C 1 A capacitor of a first-order RC link; self-discharging loop is formed by an energy storage capacitor C eff And a self-discharge resistor R SD In series configuration as shown in fig. 2.
The detection loop consists of a constant voltage source, an ammeter, a voltmeter and a power battery, as shown in fig. 3. According to the electrical principle, the current in the detection loop and other elements of the model have an s-domain relationship as shown in the formula (1):
wherein I is d (s) is the current in the external loop that can be measured, V eq Is a constant voltage source voltage, V OCV Is open circuit voltage, R eq Is the internal resistance of the equipment.
As can be seen from fig. 4 (a), the loop current i d Eventually converging to the internal self-discharge current value, but the convergence speed is slow. In order to realize rapid prediction of loop current, the derivation formula is shown as formula (2):
due to self-discharge resistance R SD It is very large that the number of the devices,formula (2) can be rewritten as:
converting the s-domain relationship to a time domain solution according to equation (3), i d ＝f(V eq ，V OCV ，R eq ，R 0 ，R SD ，C eff ，R 1 ，C 1 …, t), also known as R 0 ＝0.03Ω，R eq ＝0.05Ω，V eq ＝3.75V，V OCV =3.73v, substituted with formula (4):
wherein,
due to e.g. C eff 、C 1 、R 1 The components are unknown and require parameter identification. By measuring the loop current before convergence, a least squares fit is used. Taking logarithm at the same time on two sides of the formula (4), and shifting the term.
And also (b)Substituted into formula (5).
By least square methodSubstituted into (4). Thereby obtaining a converged loop current as shown in fig. 4 (b).
The previous description of the embodiments is provided to facilitate a person of ordinary skill in the art in order to make and use the present invention. It will be apparent to those skilled in the art that various modifications can be readily made to these embodiments and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above-described embodiments, and those skilled in the art, based on the present disclosure, should make improvements and modifications without departing from the scope of the present invention.
Claims (6)
1. The method for rapidly detecting the short-circuit current in the battery is characterized by comprising the following steps of:
(1) Modeling the power battery monomer by adopting a first-order RC equivalent circuit model;
(2) Deducing a self-discharge current fitting formula;
(3) Determination of open circuit voltage V of power battery cell using voltmeter OCV ；
(4) At a determined open circuit voltage V OCV By means of a constant-pressure source V eq Charging and discharging the power battery monomer;
(5) Determining current change i in loop by ammeter d ；
(6) Predicting self-discharge current convergence result I by adopting self-discharge current fitting formula d ；
(7) And determining whether the power battery monomer is internally short-circuited or not according to the self-discharge current convergence result.
2. The method according to claim 1, wherein in the step (1), the first-order RC equivalent circuit model includes an internal impedance portion and an internal self-discharge loop portion.
3. The method for rapid detection of short-circuit current in a battery according to claim 2, wherein the internal impedance portion is constituted by an ohmic resistor R 0 Is connected with an RC link in series.
4. The method for rapidly detecting a short-circuit current in a battery according to claim 2, wherein the internal self-discharge loop portion is formed by an energy storage capacitor C eff And a self-discharge resistor R SD And the two are connected in series.
5. The method for rapidly detecting a short-circuit current in a battery according to claim 2, wherein in the step (2), the self-discharge current fitting formula is i d ＝f(V eq ，V OCV ，R eq ，R 0 ，R SD ，C eff ，R 1 ，C 1 ...，t)
Wherein V is eq Is a constant voltage source voltage, V OCV Is open circuit voltage, R eq For the internal resistance of the equipment, R 0 Ohmic resistance R of first-order RC equivalent circuit model SD Is a self-discharge resistor C eff R is the energy storage capacitor 1 Resistance of first-order RC link, C 1 Is the capacitance of the first-order RC link.
6. The method for rapid detection of short-circuit current in a battery according to any one of claims 1 to 5, wherein in said step (6), a pre-treatment is employedThe measurement method is to fit the current I by using a least square method d The curve before convergence obtains the relevant parameters, and the residual curve is drawn according to the relevant parameters to obtain I d The converged curve is used for obtaining the self-discharge current convergence result I d 。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410224721.4A CN117890824A (en) | 2024-02-28 | 2024-02-28 | Method for rapidly detecting short-circuit current in battery |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410224721.4A CN117890824A (en) | 2024-02-28 | 2024-02-28 | Method for rapidly detecting short-circuit current in battery |
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| Publication Number | Publication Date |
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| CN117890824A true CN117890824A (en) | 2024-04-16 |
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| CN202410224721.4A Pending CN117890824A (en) | 2024-02-28 | 2024-02-28 | Method for rapidly detecting short-circuit current in battery |
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| CN (1) | CN117890824A (en) |
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- 2024-02-28 CN CN202410224721.4A patent/CN117890824A/en active Pending
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